Viruses linked to algae that control coral health

Scientists have discovered two viruses that appear to infect the single-celled microalgae that reside in corals and are important for coral growth and health, and they say the viruses could play a role in the serious decline of coral ecosystems around the world.

These viruses, including an RNA virus never before isolated from a coral, have been shown for the first time to clearly be associated with these microalgae called Symbiodinium. If it’s proven that they are infecting those algae and causing disease, it will be another step toward understanding the multiple threats that coral reefs are facing.

The research was published today in the ISME Journal, in work supported by the National Science Foundation.

“We’re way behind in our knowledge of how viral disease may affect coral health,” said Adrienne Correa, a researcher with the Department of Microbiology at Oregon State University. “If viral infection is causing some bleaching, it could be important in the death of corals and contribute to reef decline. This potential threat from viruses is just starting to be recognized.”

Corals co-exist with these algae in a symbiotic relationship, scientists say, in which the algae provide energy to the coral, and contribute to the construction of reefs. The coral in turn offers a place for the algae to live and provides nutrients for it.